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1. What is RDBMS?
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2. What is a primary key?
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3. What are the Different Types of Constraints?
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4. What is the difference between WHERE and HAVING clauses in SQL Server?
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5. What’s the difference between TRUNCATE and DELETE?
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6. What’s the difference between DROP and DELETE?
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7. What is the difference between the 'in' clause and the 'between' clause in SQL?
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8. What is the difference between a primary key and a unique key?
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9. What is a "TRIGGER" in SQL?
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10. What is Normalization?
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11. What is denormalization?
medium
12. What is view in SQL and why it is used?
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13. What are the different ways to replace NULL values in SQL Server?
medium
14. What is the difference between clustered and non-clustered index in SQL?
medium
15. What is the SQL CASE statement used for? Explain with an example?
medium
16. What is ACID property in a database?
medium
17. How to avoid duplicate records in a query?
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18. How to find a duplicate record?
medium
19. What is the difference between NULL value, Zero, and Blank space?
medium
20. How to Test for NULL Values?
medium
21. What is a DEFAULT constraint?
medium
22. How can you create an empty table from an existing table?
medium
23. What is the usage of SQL functions?
medium
24. Why we use HAVING keyword with GROUPBY function instead of WHERE keyword?
medium
25. What are the different DCL commands in SQL?
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26. What is CHECK Constraint?
medium
27. When should we create an index?
medium
28. What are database constraints?
medium
29. What is the difference between union and join?
medium
30. What is Auto Increment field?
medium
31. Explain about aggregate functions in SQL.
medium
32. What is the use of NVL function?
medium
33. What are scalar functions in SQL?
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34. How can you fetch common records from two tables?
hard
35. What are the type of locks?
hard
36. What are the different types of a subquery?
hard
37. How do you optimize your SQL query?
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38. Write an SQL query to get the third maximum salary of an employee?
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39. You have a table with three columns: Amount1, Amount2, and Amount3. In a single row only one of these three columns will have a value and the other two will be null. Write a SQL query to retrieve the values from these columns.
hard
40. What is difference between Clustered Index and Non-Cluster Index?
hard
41. Write a query to create an empty table from an existing table?
hard
42. What is the use of Execution plan in SQL?
hard
43. Write SQL Query to find employees that have same name and email.
hard
44. How can you insert NULL values in a column while inserting the data?